Find out how the beefy drug got there

Just in time for Halloween, here's a study that could be the premise of a horror flick. According to a new report published in the journal Science, the anabolic steroid that makes beef (and bodybuilders) bigger may be able to regenerate itself and shapeshift in water.

Trenbolene acetate, the high-value steroidal growth promoter used extensively in the non-organic beef and cattle industry, doesn't appear to rapidly break down in water as it was once thought to, say University of Iowa researchers. Under the right conditions, the steroid retains enough of a chemical residue to regenerate itself, prolonging the life of the drug in the environment with unknown consequences. This could have broader implications, as other drugs once believed to be safe and to break down readily might actually linger in the environment as well.

"We're finding a chemical that is broadly utilized to behave in a way that is different from all our existing regulatory and risk-assessment paradigms," says David Cwiertny, PhD, assistant professor in engineering at the University of Iowa and one of the paper's co-authors. "What our work hopefully will do is help us better understand and assess the environmental fate of emerging contaminant classes. There are a variety of bioactive pharmaceuticals and personal care products that we know are present in trace amounts in our water supply. We should use what we're learning about trenbolone to more closely scrutinize the fate and better mitigate the impact of these products in the environment."

About 20 million cows receive trenbolone acetate; the drug is implanted in their ears. The concern is that the trace amount of hormone-like drugs in the water supply will cause damaged fertility in some aquatic species.

In the study, researchers collected water from a river and samples taken from a pond at a cattle range area. Researchers noted that drug components acted differently depending on the time of day. "We knew something unique was going on," Dr. Cwiertny says. "In daylight, it essentially hides in another form to evade analysis and detection, and then at nighttime, it readily grows back."